As is known in the art, the visual perception of a white substance can be altered through the deposition of a blue pigment and/or a blue dye. For example, blue dye and/or blue pigment added to oral care products may be deposited onto teeth, thereby allowing the off-white and/or yellow color of the teeth to appear whiter to the human eye.
While these oral care products provide effective whitening after only a single use, the blue dye and/or blue pigment may only remain deposited on the teeth for a limited duration, thereby allowing the yellow stains to eventually reappear. Additionally, increasing the relative concentration of the blue dye and/or the blue pigment does not increase the duration of deposition. Instead, the relatively higher concentrations may result in an increased deposition of the blue dye and/or blue pigment, which may make the teeth appear blue and/or stain soft tissues of the mouth. Accordingly, improved oral care compositions and methods for prolonged deposition of the blue dye and/or blue pigment are desired.